The primary objectives of this study are to determine the maximum tolerated dose for TAC-101 in patients with malignancies unresponsive to standard therapy or for which there is no standard treatment, and to evaluate the safety of chronic daily adminisstration of TAC-101. Secondary objectives are to study the pharmacokinetics of TAC-101 in patients with cancer, and to detect any evidence of antitumor activity of TAC-101. This escalating study will enroll three subjects per dose level, with 6 subjects at the maximum tolerated dose.